The spontaneous breathing trial is of low predictive value regarding spontaneous breathing ability in subjects with prolonged, unsuccessful weaning

BACKGROUND: The spontaneous breathing trial (SBT) is a well-established diagnostic test for predicting extubation failure in intubated intensive care unit (ICU) patients. However, the SBT has not been evaluated in a specific cohort of tracheostomized patients in whom weaning is prolonged and ultimately unsuccessful. OBJECTIVE: The aim of the trial was to investigate the relevance of SBT failure criteria in chronic respiratory failure subjects undergoing long-term invasive home mechanical ventilation following tracheostomy and weaning failure. METHODS: Measurement of all established failure criteria including pneumotachygraphical assessment of the rapid shallow breathing index (RSBI) took place during an SBT. The decision to continue spontaneous breathing was based on failure criteria as well as the subjective willingness of the patient. RESULTS: Fifteen subjects with a median age of 58 years (interquartile range [IQR] 44–74) were studied; 10 with COPD, 4 with neuromuscular diseases and 1 with both. Twelve subjects met the SBT failure criteria within 30 min, but one third of these subjects were still able to continue with spontaneous breathing. In contrast, 3 subjects could not be weaned despite the SBT being successful. An increased RSBI was the most frequently observed SBT failure criterion (57% of all SBT). However, the SBT varied substantially in individual subjects who were able to sustain spontaneous breathing, despite having reached the cut-off for SBT failure. CONCLUSION: The SBT was of low predictive value regarding spontaneous breathing ability in chronic respiratory failure subjects with prolonged, unsuccessful weaning.